Analyzing the Impact of Different Microstructure and Active Stress Models on Peak Systolic Kinematics
摘要
Cardiac contraction models offer insight into cardiac performance in health and disease, and may help testing therapies and interventions. Before their use, several validation criteria need to be satisfied. Many model components can be introduced or modified in order to achieve the sought validation criteria. In this study, we focus on the role of cardiac microstructure and active/passive material models in an extended Hill formulation toward achieving physiological peak systolic kinematic values. In addition to cardiac strain values, apical and basal twist, and low tissue compressibility, we consider criteria based on microstructure mobility, i.e., fiber steepening at endocardium and epicardium, and global absolute E2A change at peak systole, where E2A represents the second eigenvector angle and characterizes the sheetlet orientation. The computational models consist of a prolate ellipsoid and an anatomically realistic left ventricle integrated with a microstructure generator with control over E2A. The results of this study highlight that the microstructure has a significant impact on achieving all validation criteria and that the investigated formulations can satisfy all validation criteria, at least qualitatively, except global absolute E2A change, which remains significantly underestimated at peak systole.